Manufacture of paper-disk bottle caps



March 12, 1940.

w. G. SOUTHAM MANUFACTURE OF PAPER-DISK BOTTLE CAPS Filed May 17, 1939 INVENT'OB ATTORNEY Patented Mar. 12, 1940 UNITED STATES ,ATENT orrlcs William Gordon Sout Canada, assignor to Limited, Montreal, Q

ham, Montreal, Quebec,

Southam Press Montreal uebec, Canada Application May 17, 1939, Serial No. 274,257

In Canada April 13, 1939 I 3 Claims.

This invention relates to improvements in the manufacture of paper-disk bottle caps provided with integral pull-tabs and has for its object the provision of improved means for. efiecting the so- 5 called stripping operation which consists in separating from the body of the cap that portion of the integral tab which is outlined in the usual manner by cutting part way through the thickness of the paper stock.

In making the bottle caps of the type mentioned herein it is customary to remove a small portion of the paper stock to provide a recess having one wall formed by that end of the outlined tab which is separated from thebody of the cap during the stripping operation. The main purpose of this recess is to facilitate raising of the tab after it has been restored to its original position following the stripping operation.

According to the present invention the stripbetween and parallel with the upper and lower surfaces of the cap, the distance between the up' per surface of the cap and said plane of cleavage being predetermined by the depth to which the cap is cut in outlining the tab.

This method of accomplishing the stripping operation has several important advantages over known methods involving theme of mechanically actuated stripping tools which are brought into direct engagement with the paper stock during the stripping operation. One objection to the use of mechanically actuated stripping tools is that they tend to tear or otherwise injure or deface the paper stock during the stripping operation. Another objection is that the use of these tools introduces various mechanical difiiculties which add materially to the cost of manufacture. These and other objections are eliminated when aid of an air blast in accordance with the present invention. The accompanying drawing is a perspective view illustrating one practical embodiment of the invention.

Referring more particularly to the drawing, 5 designates a pneumatic tab stripping mechanism including a base 6 having its upper surface recessed to provide a longitudinally extending guide groove I. A transversely extending pipe 8 is ping of the tab from the body of the cap is I the stripping operation is accomplished with the clamped in a bracket. 9 mounted on the base at one side of groove 1. One end of this pipe is bent in the longitudinal direction of the base to provide a nozzle extension II) having its discharge opening I I centered between the side walls of the 5 groove' The other end of pipe 8 is connected, through fiexible tube I2 and valve I3, to a compressed air supply line I4. The casing of valve I 3 is provided with a vertical valve bore I5 and an intersecting horizontal bore I6, the latter form- 10 ing a connecting passage between tube 82 and supply line I4. A cylindrical valve plug I1 is slidably mounted in valve bore I 6 and is provided with an annular groove or port !8. A spring I9 acts against a head 20 .at the upper end of plug I7 and normally serves to hold the latter in an elevated or valve closing position. In this position of plug I! the annular groove or port I8 is located above the horizontal bore or air passage I6. At suitably timed intervals the valve plug I1 is depressed by a cam 22 so that the annular groove or port I8 is aligned with the horizontal bore or air passage I6. In this open position of the valve compressed air passes from the supply line I4 through port I6 and tube I2 to pipe 8 and 25 is discharged through the opening II of the nozzle extension III.

At this point it is deemed advisable to refer briefly to the series of operations ordinarily followed in producing paper-disk bottle caps of the type with which this invention is concerned. Such caps are formed from a blank comprising a travelling strip of paper or cardboard such as that indicated at 23 in the present drawing. The initial operation in the formation of each cap consists in removing a portion of the stock from the upper surface of the blank to provide a recess 24. In the next operation the upper surface of the blank is cut as indicated at 25 to outline the sides and one end of the pull tab 26, it being noted 4 0 that the outlined end of the tab forms one wall of the recess 24. The next operation is the stripping operation which consists in separating the outlined portion of the tab blank from the body portion of the blank. The blank is then passed to a stapling mechanism which serves to drive a staple 21 through the blank at the base of each tab. The final operation consists in punching from the blank a plurality of circular disks or bottle caps 28 each including within itsboundaries .60

a pull tab 26 and the adjoining recess 24. Other operations, such as the return of each pull tab to its normal flat position after being raised by the stripping operation and the waxing of the blank,

also form part of the complete process of manufacture but have no particular bearing on the present invention.

The pneumatic stripping mechanism provided in accordance with the present invention is preferably located between the tab outlining mechanism and the stapling mechanism. As the blank comes from the tab outlining mechanism it is passed through the groove 1 of base 8 on its way to the stapling mechanism. Since the blank travels in the direction indicated by the arrow it will be noted that the outlined end of each pull tab 26 and the adjacent recess 24 passes directly beneath the nozzle opening ll. As each tab 26 reaches a position approximating that indicated at X the Valve 13 is opened so that a blast of compressed air is directed into the recess 24 and against the adjacent outlined end of the tab 26 with sufficient force to separate or strip the outlined portion of the tab from the body of the blank, the plane of cleavage between the outlined portion of the tab and the body of the blank being parallel with the upper face of the blank and being at a depth determined by the depth of the tab outlining cut or incision 25.

While I have described one practical embodiment of this invention it will be understood that the essential feature resides in the utilization of an air blast for stripping the outlined pull tab of each cap from the body of the cap or cap forming blank. It will therefore be understood that the invention is not restricted to the specific embodiment illustrated in the present drawing but may be reduced to practice in various other ways within the scope and spirit of the appended claims. Having thus described my invention, what I claim is:

1. That step in the manufacture of a paperdisk bottle cap which is out to a depth less than the thickness of the paper stock to outline the sides and one end of an integral pull-tab which comprises stripping or separating the so outlined portion of the tab from the body of the stock by directing a blast of air against the outlined end of the tab.

2. In the manufacture of a paper-disk bottle cap provided with an integral pull-tab the steps which consist in cutting the cap to a depth less than the thickness of the paper stock to outline the sides and one end of the tab and then separating the so outlined tab from the body of the stock by directing a blast of air against the outlined end of the tab.

3. In the manufacture of a paper-disk bottle cap provided with an integral pull tab the steps which consist in removing a small portion of the paper stock to provide a recess in the upper surface of the cap, then cutting the cap to a depth less than the thickness of the stock to outline the sides and one end of a pull-tab so that the outlined end of the tab forms one wall of said recess and then separating the outlined tab portion from the body of the cap by directing a blast of air into .5

said recess and against the adjacent outlined end of the tab.

WILLIAM GORDON SOUTHAM. 

